An analysis of B → η′K decays using a global fit in QCD factorization

In the framework of QCD factorization, we study B⁺⁽⁰⁾ → η′K⁺⁽⁰⁾ decays. In order to more reliably determine the phenomenological parameters X_H and X_A arising from end-point divergences in the hard spectator scattering and weak annihilation contributions, we use the global analysis for twelve B → PP and VP decay modes, such as B → ππ, πK, ρπ ρK, et cetera, but excluding the modes whose (dominant) internal quark-level process is b → ss̄s. Based on the global analysis, we critically investigate possible magnitudes of X_H,A and find that both large and small X_H,A terms are allowed by the global fit. In the case of the large X_H,A effects, the standard model (SM) prediction of the branching ratios (BRs) for B⁺⁽⁰⁾ → η′K⁺⁽⁰⁾ is large and well consistent with the experimental results. In contrast, in the case of the small X_H,A effects, the SM prediction for these BRs is smaller than the experimental data. Motivated by the recent Belle measurement of sin(2φ₁) through B⁰ → φK_s, if we take into account possible new physics effects on the quark-level process b → ss̄s, we can explicitly show that these large BRs can be understood even in the small X_H,A case. Specifically, we present two new physics scenarios: R-parity violating SUSY and R-parity conserving SUSY.